[RFC 01/19] extcon: add extcon-odroid-usbotg driver

[Robert Baldyga]

This patch adds extcon driver for Odroid U3, U3+ and X boards.
It recognizes type of USB cable connected to Odroid board basing on
two signal lines VBUS_DET and OTG_ID (the second one is present only
on Odroid U3+ board).

Following table of states presents relationship between this signals
and detected cable type:

state    | VBUS_DET |  OTG_ID
-------------------------------
USB      |    H     |    H
USB_HOST |    H     |    L
disconn. |    L     |    H
USB-HOST |    L     |    L

This driver is based on extcon-gpio driver.

Signed-off-by: Åukasz Stelmach <l.stelmach@xxxxxxxxxxx>
Signed-off-by: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
---
 drivers/extcon/Kconfig                |   4 +
 drivers/extcon/Makefile               |   1 +
 drivers/extcon/extcon-odroid-usbotg.c | 256 ++++++++++++++++++++++++++++++++++
 3 files changed, 261 insertions(+)
 create mode 100644 drivers/extcon/extcon-odroid-usbotg.c

diff --git a/drivers/extcon/Kconfig b/drivers/extcon/Kconfig
index 6a1f7de..891dca3 100644
--- a/drivers/extcon/Kconfig
+++ b/drivers/extcon/Kconfig
@@ -93,4 +93,8 @@ config EXTCON_SM5502
 	  Silicon Mitus SM5502. The SM5502 is a USB port accessory
 	  detector and switch.
 
+config EXTCON_ODROID_USBOTG
+	tristate "Extcon Odroid U3, U3+, X and XU USB OTG port"
+	depends on OF_GPIO
+
 endif # MULTISTATE_SWITCH
diff --git a/drivers/extcon/Makefile b/drivers/extcon/Makefile
index 0370b42..514384e 100644
--- a/drivers/extcon/Makefile
+++ b/drivers/extcon/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_EXTCON_MAX8997)	+= extcon-max8997.o
 obj-$(CONFIG_EXTCON_PALMAS)	+= extcon-palmas.o
 obj-$(CONFIG_EXTCON_RT8973A)	+= extcon-rt8973a.o
 obj-$(CONFIG_EXTCON_SM5502)	+= extcon-sm5502.o
+obj-$(CONFIG_EXTCON_ODROID_USBOTG) += extcon-odroid-usbotg.o
diff --git a/drivers/extcon/extcon-odroid-usbotg.c b/drivers/extcon/extcon-odroid-usbotg.c
new file mode 100644
index 0000000..7f71c48
--- /dev/null
+++ b/drivers/extcon/extcon-odroid-usbotg.c
@@ -0,0 +1,256 @@
+/*
+ *  drivers/extcon/extcon-odroid-usbotg.c
+ *
+ *  USB cable extcon driver for Odroid U3, Odroid U3+ and Odroid X
+ *
+ * Copyright (C) 2014 Samsung Electronics
+ * Author: Lukasz Stelmach <l.stelmach@xxxxxxxxxxx>
+ * Author: Robert Baldyga <r.baldyga@xxxxxxxxxxx>
+ *
+ * based on drivers/extcon/extcon-gpio.c
+ * Copyright (C) 2008 Google, Inc.
+ * Author: Mike Lockwood <lockwood@xxxxxxxxxxx>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/extcon.h>
+#include <linux/extcon/extcon-gpio.h>
+#include <linux/delay.h>
+
+enum {
+	EXTCON_CABLE_USB = 0,
+	EXTCON_CABLE_USB_HOST,
+
+	_EXTCON_CABLE_NUM,
+};
+
+static const char * const odroid_usbotg_cable[] = {
+	[EXTCON_CABLE_USB] = "USB",
+	[EXTCON_CABLE_USB_HOST] = "USB-HOST",
+
+	NULL,
+};
+
+struct odroid_usbotg_data {
+	struct extcon_dev *edev;
+	struct gpio_desc *otg_id;
+	struct gpio_desc *vbus_det;
+	int otg_id_irq;
+	int vbus_det_irq;
+	unsigned long debounce_ms;
+};
+
+/*
+ * state    | VBUS_DET |  OTG_ID
+ * -------------------------------
+ * USB      |    H     |    H
+ * USB-HOST |    H     |    L
+ * disconn. |    L     |    H
+ * USB-HOST |    L     |    L
+ *
+ * Only Odroid U3+ has OTG_ID line. U3 and X versions can detect only
+ * USB slave cable.
+ */
+
+static void odroid_usbotg_detect_cable(struct odroid_usbotg_data *extcon_data)
+{
+	int state;
+
+	mdelay(extcon_data->debounce_ms);
+
+	if (extcon_data->otg_id)
+		state = (gpiod_get_value(extcon_data->vbus_det) << 1) |
+			gpiod_get_value(extcon_data->otg_id);
+	else
+		state = (gpiod_get_value(extcon_data->vbus_det) << 1) | 1;
+
+	dev_dbg(&extcon_data->edev->dev, "cable state changed to %d\n", state);
+
+	if (state & 0x1)
+		extcon_set_cable_state_(extcon_data->edev,
+			EXTCON_CABLE_USB_HOST, false);
+	if (state != 0x3)
+		extcon_set_cable_state_(extcon_data->edev,
+			EXTCON_CABLE_USB, false);
+
+	if (!(state & 0x1))
+		extcon_set_cable_state_(extcon_data->edev,
+			EXTCON_CABLE_USB_HOST, true);
+	else if (state == 0x3)
+		extcon_set_cable_state_(extcon_data->edev,
+			EXTCON_CABLE_USB, true);
+}
+
+static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
+{
+	struct odroid_usbotg_data *extcon_data = dev_id;
+
+	odroid_usbotg_detect_cable(extcon_data);
+
+	return IRQ_HANDLED;
+}
+
+static int odroid_usbotg_parse_dt(struct platform_device *pdev,
+				    struct odroid_usbotg_data *extcon_data)
+{
+	struct device_node *np = pdev->dev.of_node;
+	u32 val;
+
+	if (!np)
+		return -ENODEV;
+
+	extcon_data->edev->name = np->name;
+
+	if (of_property_read_u32(np, "debounce", &val) != 0)
+		val = 50;
+	extcon_data->debounce_ms = val;
+
+	return 0;
+}
+
+static int odroid_usbotg_probe(struct platform_device *pdev)
+{
+	struct odroid_usbotg_data *extcon_data;
+	int ret = 0;
+
+	extcon_data = devm_kzalloc(&pdev->dev,
+		sizeof(struct odroid_usbotg_data), GFP_KERNEL);
+	if (!extcon_data)
+		return -ENOMEM;
+
+	extcon_data->edev = devm_kzalloc(&pdev->dev, sizeof(struct extcon_dev),
+					 GFP_KERNEL);
+	if (IS_ERR(extcon_data->edev)) {
+		dev_err(&pdev->dev, "failed to allocate extcon device\n");
+		return -ENOMEM;
+	}
+	extcon_data->edev->supported_cable = odroid_usbotg_cable;
+
+	ret = odroid_usbotg_parse_dt(pdev, extcon_data);
+	if (IS_ERR_VALUE(ret)) {
+		dev_err(&pdev->dev, "failed to get data from device tree\n");
+		return ret;
+	}
+
+	/* gpios */
+	extcon_data->vbus_det = devm_gpiod_get(&pdev->dev, "vbus-det");
+	if (IS_ERR(extcon_data->vbus_det)) {
+		dev_err(&pdev->dev, "failed to get vbus_det gpio\n");
+		return PTR_ERR(extcon_data->vbus_det);
+	}
+	extcon_data->otg_id = devm_gpiod_get_optional(&pdev->dev, "otg-id");
+
+	extcon_data->edev->dev.parent = &pdev->dev;
+	ret = extcon_dev_register(extcon_data->edev);
+	if (ret < 0)
+		return ret;
+
+	/* irq */
+	extcon_data->vbus_det_irq = gpiod_to_irq(extcon_data->vbus_det);
+	if (extcon_data->vbus_det_irq < 0) {
+		dev_err(&pdev->dev, "failed to get irq from vbus_det\n");
+		ret = extcon_data->vbus_det_irq;
+		goto err;
+	}
+	ret = request_threaded_irq(extcon_data->vbus_det_irq, NULL,
+				   gpio_irq_handler, IRQF_ONESHOT |
+				   IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+				   pdev->name, extcon_data);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "failed to request vbus_det irq\n");
+		goto err;
+	}
+
+	if (extcon_data->otg_id) {
+		extcon_data->otg_id_irq = gpiod_to_irq(extcon_data->otg_id);
+		if (extcon_data->otg_id_irq < 0) {
+			dev_err(&pdev->dev, "failed to get irq from otg_id\n");
+			ret = extcon_data->otg_id_irq;
+			goto err;
+		}
+		ret = request_threaded_irq(extcon_data->otg_id_irq, NULL,
+				gpio_irq_handler, IRQF_ONESHOT |
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+				pdev->name, extcon_data);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "failed to request otg_id irq\n");
+			goto err;
+		}
+	}
+
+	platform_set_drvdata(pdev, extcon_data);
+	/* Perform initial detection */
+	odroid_usbotg_detect_cable(extcon_data);
+
+	dev_dbg(&pdev->dev, "probe: success\n");
+
+	return 0;
+
+err:
+	extcon_dev_unregister(extcon_data->edev);
+
+	return ret;
+}
+
+static int odroid_usbotg_remove(struct platform_device *pdev)
+{
+	struct odroid_usbotg_data *extcon_data = platform_get_drvdata(pdev);
+
+	free_irq(extcon_data->vbus_det_irq, extcon_data);
+	if (extcon_data->otg_id)
+		free_irq(extcon_data->otg_id_irq, extcon_data);
+	extcon_dev_unregister(extcon_data->edev);
+
+	return 0;
+}
+
+static const struct of_device_id odroid_usbotg_of_match[] = {
+	{ .compatible = "extcon-odroid-usbotg" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, odroid_usbotg_of_match);
+
+static struct platform_driver odroid_usbotg_driver = {
+	.probe		= odroid_usbotg_probe,
+	.remove		= odroid_usbotg_remove,
+	.driver		= {
+		.name	= "odroid-usbotg",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(odroid_usbotg_of_match)
+	},
+};
+
+static int __init odroid_usbotg_init(void)
+{
+	return platform_driver_register(&odroid_usbotg_driver);
+}
+
+subsys_initcall(odroid_usbotg_init);
+
+static void __exit odroid_usbotg_cleanup(void)
+{
+	platform_driver_unregister(&odroid_usbotg_driver);
+}
+
+module_exit(odroid_usbotg_cleanup);
+
+MODULE_AUTHOR("Lukasz Stelmach <l.stelmach@xxxxxxxxxxx>, Robert Baldyga <r.baldyga@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("USB OTG extcon driver for Odroid U3, U3+ and X");
+MODULE_LICENSE("GPL");
-- 
1.9.1

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